Spark plug



R. BIZZARRO July 31, 1934.

SPARK PLUG Filed Sept. 4, 1931 Fl 6. 2. INVENTOR RALPH BIZZARRO BY ms ATTORNEY Patented July 31, 1934 UNITED STATES SPARK PLUG Ralph Biuarro, New York, N. Y., minor to Joseph F. Starr, New York, N. Y.

Application September 4, 1931, Serial No. 561,145 6 Claims. (Cl. 123-169) This invention relates to internal combustion engine accessories and more particularly refers to improvements in spark plugs, such as are used for igniting the explosive charge in the cylinders of an automotive engine.

Spark plugs are ordinarily made in permanently assembled form, making it impossible, or at least difficult, to utilize the various component parts thereof when for any reason a spark plug 10 has ceased to function in a satisfactory manner.

Among other factors the formation of carbon upon the terminals is responsible for a reduced efficiency and at times total disability of a spark plug. Another factor is the tendency of the terminals between which the spark occurs to become in time pitted or-worn, requiring the use of a flle in order .to reestablish their active surfaces to a clean and smooth condition. However, the use of a file in such occurrences frequently resuits in rendering the spark plug totally unfit for use, especially because the spark gap between the terminals should be carefully adjusted.

Another objectionable feature of ordinary spark plugs is that when the body of the plug becomes overheated the generation of sparks temporarily ceases until the spark plug is given a chance to cool off. This constitutes a serious inconvenience in motoring, especially when climbing hills, when the engine is made to run at full speed and the frequency of both sparks and explosions taking place in each cylinder causes overheating of the spark plugs.

In such contingencies it becomes necessary to reduce the speed of the motor or to stop it entirely for short periods, a performance which is fraught with danger when a car is running up hill.

The primary object of this invention is to provide a spark plug of a novel and improved design, the construction of which is such as to insure the continuous generation of sparks under all conditions.

Another object is to provide in a spark plug of the character specified a plurality of sets of terminals, the terminals of each set being separated by a spark gap of proper width, the resulting structure insuring the generation of sparks between at least one of the sets of terminals even if one or more of the other sets are temporarily or permanently disabled.

A further object 'of the invention is to provide a spark plug in which the parts which are most subject to becoming damaged or worn are removable so as to be replaceable at small expense, thus permitting of otherwise preserving the spark plug structure for a relative long period of time, decreasing the cost of engine upkeep.

A still further object is to provide in a spark plug of the character specified a novel and improvedtype of adjustable terminal, protected by heat insulation, so as to insure the generation of a spark even under the most severe conditions of running.

Other objects and advantages of the present invention will more fully appear as the description proceeds and will be set forth and claimed in the appended claims.

My invention is illustrated by way of example in the accompanying drawing, in which:

Fig. 1 is a view in elevation, partly sectioned, of a spark plug embodying some of the features of my invention;

Fig. 2 is a cross sectional view of the same through line 2-2 of Fig. 1;

Fig. 3 is a view in elevation, partly sectioned, of 76 another spark plug of preferred construction also embodying my invention; and

Fig. 4 is a cross sectional view of the same through line 4-4 of Fig. 3.

Referring to Figs. 1 and 2, '10 designates the 80 body of a spark plug, which has its lower end threaded as shown at 11, so as to be insertable in the cylinder head of an internal combustion engine.

The upper end of body 10 preferably has a polygonal outline, as shown at 12, so as to be engageable by an ordinary wrench, and the intermediate portion of said body is preferably formed with a series of circular grooves 13, increasing the radiating surface of said body.

The body 10 is of hollow construction, forming a lower cylindrical chamber 14 through which may be inserted the lower end 15 of a porcelain insulator 16. The upper end of chamber 14 is enlarged, forming a seat provided with a gasket 17, against which rests the shoulder 18 of the porcelain insulator. The porcelaininsulator is held in position within the body of the plug by a nut 19, having a recessed opening forming a'seat provided with another gasket 20, resting against the shoulder formed by the upper end of the enlarged portion 21 of the insulator.

The insulator 16 is provided with an axial through passage terminating at the upper end in an enlarged chamber or recess, within which may be cemented an internally threaded metal bushing 22. I

Within said bushing may be screwed a socket 23 formed with a head 24, said socket hav- 8 a! threaded axial opening within which may I be screwed the threaded upper end 25 of an electrode 26, extending through and beyond the axial passage provided in the insulator.

The electrode is preferably formed with a turned down lower end 27, forming with the upper portion thereof a shoulder 28 resting against a corresponding seat formed in the axial passage of the insulator.

The extreme lower end of the electrode proiecting beyond the insulator is threaded, as shown at 29, and the upper end thereof is also threaded for insertion through socket 23 and also to receive a clamping nut 30.

The lower tip end of the electrode is turned down to form a terminal 31 and the lower end of the body 10 is formed with a threaded recess adapted to receive the threaded upper end 32 of an open side cap 33, with which the lower end of the body 10 is equipped.

- The disk shaped lower end 34 of said cap is connected to its annular threaded upper end 32 by two diametrically opposite legs 35, 36.

Said lower end 34 is furthermore formed with a recessed central opening 37 within which is housed a heat insulating structure comprising an upper and a lower thickness of mica 42, 39, and a metallic washer 40 inserted therebetween', said heat insulating structure being formed with a central threaded opening through which is inserted the threaded body 41 of another terminal 42 co-axial with terminal 31.

By virtue of this construction it is at all times possible to remove terminal 38 for the purpose of cleaning the two opposing surfaces between which the spark jumps, and it is also possible at all times to properly adjust the width of the spark gap.

An important feature of this construction is that the heat insulating structure formed by the onto the lower end 29 of the electrode so as to rest against the tip end of the lower portion 15 of the insulator, assisting socket 23 in holding the electrode in position.

when member 43 is thus inserted in posi ion the bar structure. formed by its two terminals 44, 45, remains directed substantially at right angles to the legs 35, 36 of the cap, spark gaps such as 46, 47, intervening between said terminals and the lower edge 48-of the annular portion 32 of the cap.

In this manner it will be observed that there are three spark gaps through which sparks may be generated, this condition of itself being sufllcient to practically insure continuity of operation. In order to take care of exceptional conditions such as arise when the engine is running under heavy load, one of said gaps is formed by a set of terminals, which is protected by heat insulation.

As before stated, bushing 22 is cemented within the recess formed at the upper end of the porcelain insulator and the cementing action is obtained by means of some suitable heat-proof insulating cement 49, which is placed within the recess of the insulator before the bushing is forced therein. The bushing 22 is preferably forced in position when assembled with socket 23 and the electrode 26, so that cement 49 will be forced to fill up every clearance space intervening between the bushing and the insulator and between the insulator and the electrode.

After the cement has become hard, the socket 23 and the electrode may be removed at any time while the bushing 22 is permanently held in position by the bindingvor anchoring action of the cement.

The use of the insulating cement improves the insulation conditions and, therefore, tends to decrease the losses or leakages which might otherwise occur.

The removable type of electrode shown in Pig. 1 is to be preferred when said electrode is formed integral with the terminal 31, as shown, in order to provide a construction whereby the electrode may be replaced without replacing the entire plug.

On the other hand, in order to insure a permanently good insulation, it is better if the central electrode is not removable once it has been assembled.

I, therefore, flnd it preferable'to use the construction shown in Figs. 3 and 4, in which the end terminal 31' is made integral with a multiple terminal member 43', which is, as in the previous case, screwed onto the lower threaded end 29' of l the electrode and is provided with two diametrically opposite terminals 44', 45.

In the construction shown in Figs. 3 and 4, th legs 35', 36', extending between the lower end of the plug body and the cap 34', are preferably 11' made integral with the body 10' itself, and the terminals 44', 45', are made to face said legs.

Moreover, the legs are each provided with a threaded opening through which may be adiustably inserted respectively, the threaded body 50, .110 51, 041 terminals 52, 53, directly opposite terminals 44', 5'.

Like in the previous case another adjustable terminal 42' is inserted directly opposite terminal 31', said terminal 42' being protected by heat 11' insulation as explained in the previous case.

By virtue of this construction the advantages of the three spark gap construction are retained and at the same time all terminals are made removable and replaceable independently of the m other elements of the spark plug.

Another advantage of this construction is that all the spark gaps are accessible for cleaning and are adjustable at will.

When this type of construction is adopted the m electrode 26' is preferably set in position permanently, and to this end, the electrode is inserted into position together with the bushing 22' screwed thereon, said bushing being forced within the cemeat 49' and becoming permanently anchored in in position after said cement has set.

The details of construction of my improved plug may vary to a certain extent from those shown without departing from the inventive idea. The drawing, therefore, will be understood as being intended for illustrative purposes only and not in a limiting sense.

I accordingly reserve the right to carry my invention into practice in all those ways and manners which may enter, fairly, into the scope of the appended claims.

I claim:

1. In a spark plug the combination, with a hollow body, an insulator mounted therein, and an electrode axially extending through said insulator, of a terminal associated with said electrode, another terminal associated with said body, cooperating with said electrode terminal for the generation of sparks, and means for heat insulating the terminal associated with said body, the 150 latter terminal being adjustable to and from the former and carried by said heat-insulating means.

2. In a spark plug the combination, with a hollow body, an insulator mounted therein, and an electrode held within said insulator, of a plurality of terminal studs associated with said body, and a multiple terminal member, having a plurality of terminal studs each coaxial with and adapted to cooperate with a companion terminal stud of said body for the generation of sparks, removably carried by said electrode.

3. In a spark plug the combination, with a hollow body, an insulator mounted therein, and an electrode held within said insulator, or a plurality of terminal studs associated with said body, a multiple terminal member, having a plurality of terminal studs adapted to cooperate with said body terminal studs for the generation or sparks, removably carried by said electrode, and heat insulating means for adjustably mounting one of the terminal studs associated with said body.

4. A spark plug comprising a hollow body, an insulator mounted therein, an open side cap at the inner end of said body, an electrode axially extending through said insulator, a terminal member coaxial therewith at'the inner end of said electrode, heat insulating means carried by said cap and another terminalmember adjustably carried by said heat insulating means, coaxial with and movable to and from said electrode terminal member.

5. A spark plug comprising a hollow body, an insulator mounted therein, an open side cap at the inner end of said body, an electrode axially extending through said insulator, a terminal coaxial therewith at the inner end of said electrode, another terminal, coaxial therewith, adjustably mounted within said cap so as to be movable to and from said electrode terminal, and means for heat insulating said movable terminal.

6. A spark plug comprising a hollow body, an insulator mounted therein, an open side cap at the inner end of said body, an electrode axially extending through said insulator, a multiple terminal member removably carried by the inner end of said electrode, said member having a terminal coaxial with said electrode, and two diametrically opposite terminals at right angles to the axis thereof, two terminals associated with the body structure, and a third terminal coaxial with said electrode, adjustably mounted through the bottom end of said cap.

RALPH BIZZARRO. 

